At the same hour on the same day of every week between 15 May and 30 September, a curious scene is played out at each of England's 500-odd designated coastal and inland bathing waters (or beaches, basically). A white van pulls up, and a man or a woman gets out. Wearing more often than not a watertight drysuit and clutching an empty, clear plastic bottle, they walk along the beach until they reach a particular spot; the same one each week. They wade straight out into the water until they are standing one metre deep, lower the bottle to half a metre below the surface, and fill it up. Then it's out again, and off to the next beach with another bottle.

What are they after? You may not want to know. The laboratories where these samples are analysed, says Nick Smart, a technical specialist at the Environment Agency, are looking for "bacteria representative of the gut content of a warm-blooded creature. Um, animal, or human."

He tries again: "Basically, organisms associated with faecal matter. They may not necessarily be harmful themselves, but they do indicate the presence of faecal pollution. They show that pathogens might be there."

Whatever other word you choose to use for this stuff, few people would dispute that its invisible presence in the water we swim in is at best unpleasant. At worst, faecal pollution can cause ear, nose and throat infections, and gastroenteritis.

England's bathing waters are undeniably far cleaner now than 25 years ago (we no longer, for one thing, routinely discharge raw sewage into the sea, as we did into the 1990s); last year, which was a bad year for bathing water quality because of heavy rainfall and flooding, some 93% of them met the current minimum European water quality standard. But there are still plenty of ways for "bacteria representative of the gut content of a warm-blooded creature" to find their way into our bathing waters – and the rules for what's permissible are about to get significantly tougher.

The EU's new Bathing Water Directive, roughly twice as strict as the current standard, comes into force in 2015. What's more, beaches rated poor under the new rules will have to display a prominent sign advising visitors not to swim there; surely any seaside town's worst nightmare. And the agency reckons about 10% of England's bathing waters that currently pass – about 55 beaches – run this risk.

Walking along Teignmouth town beach in Devon, Smart explains to Chris Smith, the affable chairman of the Environment Agency, that this is, potentially, one of them (though he's confident it will be brought up to scratch in good time).

Unlike neighbouring beaches such as unpolluted Holcombe or pristine, isolated Ness cove – accessible only by tunnel – Teignmouth town beach fronts a popular Victorian seaside town. Its issues, Smart says, are legion. "You've got some CSO problems," says Smart: during sudden, severe rainfall, when sewers are overwhelmed, Britain's 31,000-odd Combined Sewer Overflows, the legacy of an outdated system that made no distinction between sewage and storm-water, discharge both types through combined outfall pipes. This may stop sewage backing up into people's homes – but it also directs it, mixed with storm-water, into streams, rivers and eventually, the sea.

'You can't see off every seagull' ... guano is a big problem under the new EU directives. Photograph: Chris Laurens/Getty Images

Water companies have invested in sewage treatment capacity and CSO improvement programmes and the problem is less severe than it was, says Smith: "But there's a lot still to do. Overflow remains a real problem, as last year shows. And as climate change starts to have an impact – more frequent periods of heavy rain, and alternating rain and drought – it will only become more difficult."

CSO pollution is not the only problem facing seaside towns which need clean bathing water if they are to continue to attract the all-important summer holidaymakers and trippers. In Teignmouth, says Smart, "there's also what we call urban diffuse pollution. And dogs. And seagulls. And across the estuary here, you've got the problems associated with a vast agricultural hinterland, right up on to Dartmoor: a lot of dairy cattle, manure, slurry, agricultural run-off. So it's a whole mix of issues. The big ones have, mostly, been sorted; now it's a series of smaller, incremental steps."

Urban diffuse pollution is the technical term for surface water from populated areas. Supposedly relatively clean, it can contain bacterial pollution from any number of sources. "Say a dog fouls a pavement or a road, just up the hill here," says Smart, gesturing behind him. "The owner doesn't bag and bin it. It rains. The rain carries the dog's faeces into a gulley, from where they enter the surface water drainage system, and eventually land up in the sea. Not many dog owners realise their behaviour can have a very real impact on bathing water quality."

Most local authorities are vigilant about dog fouling on their beaches. But a successful campaign against pavement fouling could ultimately prove just as important for a successful summer tourist season. As could a sustained campaign discouraging visitors from feeding the seagulls, and seafront cafes from leaving leftovers on tables, Smart points out.

Seagulls are "a big, big problem under the new directive", he says. "Before, they were more or less background noise. But with these new testing criteria they're going to become a real issue." Smart points to Teignmouth pier and its arcade. "A seagull eats his fill of chips or sandwich or whatever, and goes and perches on the roof of the pier buildings," he says. "He does what he has to do, it rains, and that guano-infested water just runs straight into the sea."

(In collaboration with South West Water and the pier's owner, incidentally, the Environment Agency recently took steps to ensure the pier's guttering and downpipes run into the town's foul water system, meaning run-off from the roof is now treated before it is discharged.)

Another major source of bathing water pollution in built-up areas is wrongly connected household drains. At one end of Teignmouth town beach, Smart leads Smith up a steep path though an attractive park to a busy road. Under the road, says Smart, are two separate drainage systems, one for both foul drains – domestic sewage, essentially – and the other for surface water, as is now common practice (until the 1960s, it wasn't. We made no distinction.) Then he points to two houses opposite, both built 10 or so years ago. "Whoever built them," he says, "connected their foul drainage to the wrong pipe. So those houses' toilets were emptying into the Brimley brook urban stream here, which flows into the Brimley brook outflow pipe, and into the sea."

This kind of mistake is alarmingly common. In the Torbay area alone, a 2010 campaign identified and fixed some 130 misconnections from toilets and sinks at a medical practice, a local supermarket, commercial units on an industrial estate, a local factory, a large Torquay hotel and a church hall, preventing some 7,500m³ of polluted water from flowing on to the bay's beaches and into the sea.

Faced with stricter bathing water standards and summers that seem to be getting ever wetter, the agency is going to have to work harder with all concerned – local authorities, farmers, homeowners and landowners, businesses, the water industry – to maintain, let alone improve, bathing water quality.

The Marine Conservation Society, which publishes the Good Beach Guide based on Environment Agency and local authority data, says last year's wet summer means 42 beaches have failed to meet the minimum European standards for bathing water quality – 17 more than in the previous year's guide. It also recommended 113 fewer beaches as having excellent water quality.

In the south-west, only 110 out of 196 beaches are recommended for excellent water quality in the 2013 guide. Sixteen beaches, including Plymouth Hoe East and West, Bude Summerleaze in Cornwall and Exmouth in Devon, failed to meet the minimum standard – 14 more than last year.

Some beaches, concedes Smart, "we will never get to Good or Excellent. There are simply too many impacts. You can't see off every seagull, or shut down a river." Plus, it can sometimes be very difficult to know exactly what the issue is. "If something's not looking right, the science can be quite tricky," he says.

"The water may be generally very clean; no problems at all. But you're talking about one sample, taken once a week. You have no real way of knowing if a seagull just pooped three inches from where you take it."

The new EU standards will help in at least one respect, though: they will judge the quality of a stretch of bathing water on the basis of four years' figures, not just one. "That," says Smith, "should reduce the impact of one very bad year."

About this article

England's polluted beaches: stop this tide of filth

This article was published on
the Guardian website
at 15.12 EDT on Sunday 7 July 2013.
A version appeared on p10 of the G2 section of the Guardian
on Sunday 7 July 2013.
It was last modified at 20.10 EDT on Wednesday 21 May 2014.
It was first published at 14.00 EDT on Sunday 7 July 2013.